how to fecth database to datagridview

hi
i am generating a billing software . i want to know how to access the database to datagridview. in datagridview if i press 1st cell it should directly the items list in another form in that another form select the item it should display all the details of item like qty price total.then if press 2nd cell same procedure must be done
sir if u can see this link u can get an idea http://www.youtube.com/watch?v=xWCi7qwfB2U 


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